walter



C. M. WALTER.

' FURNACE FOR THE HEAT TREATMENT OF METALS.

APPLICATIGN FILED AUG.6. 191i.

3 SHEETSSHEET 1.

1 ,3U3,4;29 Patented May 13, 1919..

C. M. WALTER.

FURNACE FOR THE HEAT TREATMENT OF METALS.

APPLICATION FILED AUG-6. 1917.

Patented May13, 1919.

3 SHEETS-SHEET 2.

C. M. WALTER.

FURNACE FOR THE HEAT TREATMENT OF METALS. APPLICATION FILED AUG-5. I917.

LBMAQQ Patented May 13,, 191%..

T a 3 SHEETS-SHEET 3 Fig. l.

run srnrns CECIL MONTAGUE WALTER, F BIRMINGHAM, ENGLAND.

FURNACE FOR THE HEAT TREATMENT OF METALS.

Specification of Letters Patent.

Patented May 13, iaia.

Application filed August 6, 1917. Serial N0. 184,743.

To all whom it may concern:

Be it known that I, (learn MONTAGUE WALTER, B. So, of Lyvden,LitchfieldRoad, Four Oaks, Birmingham, England, engineer, subject of the King ofGreat Britain, have invented certain new and useful lmprovements in'andRelating to Furnaces for the Heat Treatment of Metals, of which thefollowing is a specification.

Thi invention comprises improvements in and relating to the heattreatment of metals such as hardening, 'te1nperi.ng,- annealing, andlike operations, in which the articles to be treated are heated in atube charged with an inert gas or a carburizing medium, and aredischarged into a quenching bath of oil, water or other'liquid withoutexposure to the atmosphere and the consequent risk of oxidation.

My invention has for its object to provide an improved tubular furnacein which the heat treatment and hardening of metals may be readilycarried out to secure uniform treatment for the articles placed therein.Uther important objects are the mounting of the tubular furnace and thearrangement of the closure device to facilitate close observation of theheat treatment.

@n the drawings.

Figure 1 is a vertical sectional view of a furnace suitable for the heattreatment of small articles.

Fig. 2 is a sectional plan on line 2-2 of Fig. 3 is a sectional view ofa suitable closure plate for the upper end of the retort tube.

Fig. 4 is a planthereof. I

Fig. 5 is a sectional view of one form of suspension device;

This exampleof the invention shows a comparatively'small furnace heatedby the combustion of gas. The retort tube or shaft a is shown ofcylindrical formation, which is preferred, and is supported or seated ina socket portion 12' of a platform or bottom plate. 0 which is securedto the outer casing or walls (i as at e Flg. 1. The lining around theretort tube a may be built upon the bottom plate a in any suitablemanner according to the design and arrangementof the heating furnace. Itis here shown as a central structure f Fig. 2, providing the combustionspace 9 around the retort a, and separated from the refractory lining hof the casing d by a space which is packed with antithermic orinsulating packing. Through the central structure f at one side is anopening leading to the combustion space for the insertion of a burnertube is and on the other side at m is shown an outlet flue from thecombustion space. In this example the burner is shown as a gas andcompressed air burner or air blast burner. The arrangement of the seatfor the tube a in the socket b admits of its being packed as at?) andforms a very efiective mounting.

The retort tube or shaft is continued below the socketed plate 0 and issealed in a bath of oil, water, or other liquid which in hardeningoperations will serve as the quenching medium; for this purpose thesocket b may be flanged at n and a wrought iron or other pipe 0 may bedetachably secured thereto to form the continuation part ofthe tube orshaft which leads from the retort portion proper to a seal or aquenching bath, so that no oxidation can take place as the articles arelowered out of the retort part of the tube. w

The carrier plate 0 is preferably above the ground level and thus thepart 0 of theretort tube or shaft may form a cooling portion.

The bath g is shown in a pit r.

An inlets. is provided preferably above the bath leading into the tuberetort so that the latter may be charged with an inert gas, such asilluminating gas. If desired any suitable carburizing medium may beintroduced into the retort, such as illuminating gas which has beenbrought into contact with ammonia vapor, or a suitable hydrocarbon, suchas petroleum vapor.

Theupper end of the tube or shaft a is shown provided with a closuredevice comprising a crown plate I? with a seat a for a cover plate 12.The latter has a mica or other window 'w and there may be a space as atw for the reception of a pyrometer. The window w is preferably set at anincline so that the pyrometeri and the work and the relation betweenthem may be observed,

Through the cover an outlet y may be provided with a pipe and a cockregulating the escape of gas from the retort a.

The articles under treatment may be suspended or supported in anyconvenient manner, for example in a basket of hard wire or of refractorymaterial suspended by wires or rods through an aperture a, packed ifnecessary, in the cover plate 0' at the top of the tube a. A suitablebasket is shown at 1 and the suspending wire at 2 and welghts 3 areshown mounted on the wire so that the basket will be retained inoscillation for some time if the wire is given a twist by turning theweights. The basket 1 is used for small work, and other work may be heldby a suitable clip on the suspension wire or rod.

Instead of the torsion device for oscillaa ing the wire a ball or otherhearing such as 4: Fig. 5 may be provided at the top of the suspensionwire 2, so that by turning the wire by hand or otherwise the basket maybe freelyrotated during heating to insure even heating of the Work.

The work is heated in the upper portion of the tube or chamber a whenthe desired temperature is obtained, or the duration of treatment isterminated, it is lowered into the continuation part of the tube andinto the seal or quenching bath. The cooled continuation part of theretort tube separates the retort from the bath and revents undue heatingof the bath by the tu be or chamber which 1s sealed therein.

Preheating of the steel may take place in'the upper part of the sametube or chamber a owing to the natural temperature grad uation therein,but if desired a second furnace surrounding an extended upper portion ofthe tube may be employed to give any desired preheating temperature tothat portion of thechamber or tube.

1. An improved furnace of the type set forth for the heat treatment ofmetals com: prising in combination a vertical refractory retort tubeclosed at its upper end with a removable closure device, and having aheated portion forheating by radiation from its walls the metals ormetal articles under treatment, and means for suspending the metals ormetal articles .therein from or through the closure device so as to beclear of the walls, and an inclosed continuation or extension of theretort tube leading to and dipping in a quenching bath so as to beeffectively' sealed therein, with an inlet in the said'continuation orextension by means of which the whole retort tube is charged with aninert gas or vapor or with a carburizing medium as desired. I

'2, An improved furnace of the type set forth comprising in combinationa vertical refractory retort tube and means for heating same, aremovable closure for the upper end of the retort and a continuation orextension from the heated portion leading-to and effectively sealed in aquenching bath, with an inlet in the continuation or extension for aninert gas or vapor carburizing medium, and torsional means for suspendinthe metals or metal articles to be trea within the retort tube, throu hsaid closure, so as to be clear of the wa s but so as to admit of theirmovements to secure equal heating.

3. A furnace of the type set forth comprising in combination a furnacecasing a refractory lining therefor supported by a bottom plate, a,chamber in sa1d lining open at the top and socketed part of the bottomplate in alinement with said chamber, a reractory retort tube in saidchamber seated in said socket, means, such as as burners in the chamber,for heating sai tube, a removable closure for the upper end of saidtube, and means for suspending articles in thetube through said closureclear of the walls of same, an extension detachably secured to saidsocket part and communicating with said tube, and a quenching bath inwhich said extension is sealed; with an inlet in said extension partimmediately above said seal so that said extension and the tube can "becharged with a gas.

4a A furnace of the type set forth comprising in combination a furnacecasing a refractory lining therefor supported by a bottom plate, achamber in said lining open at the top and a socketed part of the bottomplate in alinement with said chamber, a

refractory retort tube in said chamber seated in said socket, means,such as gas burners in the chamber, for heating said tube, a

- removable closure for the top of said tube said closure having anaperture to receive a pyrometer and a window adjacent to said apertureand set at a slight angle, means for suspending articles in the tubethrough said closure clear of the walls of same, an extensiondeta'chably secured to said socket part and communicating with saidtube, and a quenching bath in which said extension is sealed; with aninlet in said extension part immediately above said seal so that saidextension and the tube can be charged with a gas.

5. A furnace of the type set forth comprising in'combination a furnacecasing a refractory lining therefor supported by a bottom plate,achamber in said lining open at the top and a socketed part of thebottom plate in alinement with said chamber, a refractory retort tube insaid chamber seated in sa1dsocket, means, such as gas burners,

1,303,420 V a a in the chamber, for heating said tube, a resaidextension part immediately above'said movable closure for thetop of saidtube and seal so that said extension and the tube can 10 means forsuspending articles in the tube be charged with a gas, and an outletthrough through said closure clear of the Walls of said closure for saidgas which may be burnt same; an extension detachably secured to forheating a regenerator for the incoming said socket part andcommunicating with fuel for heating the tube.

said tube, and a quenching bathin which In Witness whereof I aflix mysignature.

said extension is sealed; with an inlet in CECIL MONTAGUE WALTER.

